PROJECT SUMMARY/ABSTRACT Competitive Supplements/Revisions for the INCLUDE SUSCEPTIBILITY TO AND RELEASE FROM MASKING IN INFANCY AND CHILDHOOD The present application will characterize speech recognition for children with Down syndrome in the context of each child?s audiological profile, cognitive functioning, and receptive language abilities. Aim 1 evaluates the relative importance of these listener factors on speech recognition in competing noise or speech using a closed-set, picture-pointing task. This task has been evaluated in our laboratory on children as young as 4 years of age, including children who are non-native speakers of English, and children with profound hearing loss. A sample of 60 school-age children with Down syndrome (5-17 years) will be recruited from the population of over 180 children with Down syndrome followed at Boys Town National Research Hospital (BTNRH) and from local community groups. Data have been collected on 87 children who are typically developing as part of the parent grant. The closed-set, picture-pointing task does not require a verbal response. While performance in noise is expected to be mediated by peripheral auditory factors (for example, audibility), performance in the speech is expected to be more heavily influenced by higher-order auditory and cognitive processes. Aim 2 assesses the extent to which children with Down syndrome capitalize on binaural auditory cues that promote segregation of target from background speech in children who are typically developing. The development of binaural hearing abilities is affected by conductive and sensorineural hearing loss, as well as perceptual processing, and is likely to be adversely impacted in children with Down syndrome as a result. Results from these experiments are significant as they will inform theory and impact clinical practice. The knowledge gained and infrastructure developed to complete the proposed experiments will provide a lasting foundation for future research focused on developing a better understanding of the mechanisms that contribute to resiliency in communication outcomes for individuals with Down syndrome.